1. Technical Field
The present invention relates generally to an apparatus and method for extracting correspondences between aerial images and, more particularly, to an apparatus and method for extracting correspondences between aerial images, which are capable of automatically calculating correspondences between aerial images using the linear characteristics of buildings based on aerial images of urban areas in which buildings occupy the majority of the photos.
2. Description of the Related Art
In order to determine correspondences between images, a method in which a human directly intervenes and manually marks corresponding points and a method of automatically calculating corresponding points have been used.
The method of automatically calculating corresponding points has developed from a method of comparing pixels between images to a method of finding identical portions by calculating the feature descriptors of the respective portions of an image and comparing the feature descriptors with feature descriptors extracted from another image.
A variety of methods using feature descriptors have been devised that range from a simple method using the pixel values of images to a method of calculating the directions of the gradients of images. Recent methods can find corresponding points at high accuracy even when image capture conditions are considerably poor.
Although the methods of comparing feature descriptors exhibit excellent performance for general photos, many identical feature descriptors are calculated due to the similarity between buildings and the similarity between parts of buildings when the methods are applied to images of urban areas including many buildings, and therefore the calculation of corresponding points using feature descriptors exhibits low efficiency.